Considerable efforts have been made for preventing the occurrence of contamination in silver halide photographic materials by intermixture of metals or metal compounds which have undesirable influences on the photographic materials during the production, packaging, preservation, processing, etc., of the photographic materials. However, in spite of such efforts, these metals or metal compounds are brought into contact with silver halide photographic materials as fine particles of them in the air, or in suspensions of solutions which results in giving stains, spots, color stains, changes of tone, etc., undesirable to the photographic materials after processing.
The metals or metal compounds having undesirable influences on silver halide photographic materials are, in particular, iron, aluminum, chromium, nickel, copper, etc., and the compounds of these metals. However, they are not limited to these mateials and include alkaline earth metals such as magnesium, calcium, strontium, etc., and the compounds of them.
The metal such as, for example, iron in the form of very fine particles is easily oxidized into Fe (II) or Fe (III) to desensitize the silver halide of a silver halide photographic material by contact with the oxidized products or Fe and Fe (II) are respectively oxidized into Fe (II) and Fe (III) with the release of electrons to sensitize the silver halide of a silver halide photographic material by contact with the electrons, whereby contaminations are formed on the silver images after processing. Also, in a color photographic material the foregoing contaminations of the silver image are converted into contaminations of color image.
Furthermore, these metals or metal compounds not only have undesirable influences on silver halide emulsions but also sometimes react with photographically useful additives (e.g., color image providing compounds such as couplers, diffusion transfer dyes, etc., sensitizing dyes, antifoggants, fading preventing agents, hardening agents, binders, etc.) to give undesirable influences, such as the occurrence of stains, spots, color stains, tone changes, etc. (hereinafter, they are generally referred to as "image contamination") to images.
Furthermore, for the preparation of processing solutions used for processing silver halide photographic materials, natural water such as well water, city water, etc., is usually used and it is known that such water contains alkaline earth metals such as calcium, magnesium, etc., and other materials dissolved therein and the kind and the contents of these materials greatly differ according to the nature of the soil with which the water was brought into contact (Chishitsu Chohsa-jo Kagaku-bunseki Seika-hyoh published by Tsusan-shoh Chishitsu Chohsa-jo; and Suishitsu Chohsahoh published by Maruzen Co., Ltd.).
Accordingly, it sometimes happens that a part of these metal ions dissolved in the processing solutions have undesirable influences during the processing of silver halide photographic materials, which results in undesirable effects on photographic properties, such as the reduction in image density, change of tone, occurrence of color turbidness, etc.
Phosphoric acid type chelating compound such as an alkali metal metaphosphate are conventionally used for preventing the occurrence of the foregoing image contaminations in silver halide photographic materials. However, such a chelating agent causes side effects as described in, for example, U.S. Pat. Nos. 3,443,951, 3,312,552 and 3,382,071. Furthermore, the foregoing U.S. Pat. No. 3,382,071 indicates that a hydroxylated polyamino-polycarboxylic acid such as an ethylenediaminetriacetic acid derivative is used as such as chelating agent but is insufficient. Moreover, Japanese Patent Application (OPI) No. 173829/82 (corresponding to U.S. Pat. No. 4,340,665) (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") discloses a combination of a phosphate and trisodium hydroxyethylenediaminetriacaetate and further U.S. Pat. No. 3,488,707, British Pat. Nos. 952,162 and 1,221,138, Japanese Patent Application (OPI) No. 120628/74, U.S. Pat. No. 3,778,268, etc. disclose chelating agents such as phosphonic acid derivatives and polyaminopolycarboxylic acid derivatives, but they show low image contamination preventing faculty or cause many side effects.
On the other hand, U.S. Pat. No. 3,312,552 discloses that an ortho-hydroxybenzylamine derivative having an amino group substituted by a 2-alkyl radical including a carboxy group is incorporated in a silver halide photographic material. However, the compound disclosed in the foregoing U.S. Patent shows a lower image contamination preventing faculty than those of the compounds used in this invention as will be described hereinafter.